Ignition & Fusebox

JimC said:

That's interesting. I'm thinking a starter is a D.C. motor and D.C. motors change direction with polarity. I can't say electric motors are my strong suit, but it's got me wondering why......

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From what I've been able to find out, if the polarity of both field winding and armature are reversed, as would be the result of changing the motor's polarity, then the motor would continue to rotate in the same direction.
If the polarity was to be reversed in only one of them, then the rotation would reverse.

That would make sense. I was thinking of power window motors. I think they reverse direction simply by changing polarity. Didn't the old rag top motors act the same? Anyway, not changing directional rotation of the starter motor simplifies going to a negative polarity. Good to know. Thanks, LAB.

I now kind of hazily remember from my old Navy days, circa 1962, that it's electric motors with a permanent magnet that change direction with polarity. Don't anyone take what I've said to the bank. I'm only ruminating here.

L.A.B. said:

I've just tested my own starter, and it does turn in the same direction when the polarity is reversed.

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What did you actually do, did you leave the wires to the soleniod & starter as they are normally ? Because my bike is at present fitted with a Boyer the white and purple wire from the ballast resistor to the solenoid via a coil is not fitted, I spoke to Boyer about this wire a few weeks ago when I bought my power box and they said it wasn't needed. The starter does work with out it.

rbt11548 said:

What did you actually do, did you leave the wires to the soleniod & starter as they are normally ?

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I simply removed the starter, and then used a battery and jump leads connected both ways.

rbt11548 said:

Because my bike is at present fitted with a Boyer the white and purple wire from the ballast resistor to the solenoid via a coil is not fitted, I spoke to Boyer about this wire a few weeks ago when I bought my power box and they said it wasn't needed. The starter does work with out it.

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The White/Purple from the solenoid is a booster wire for the original points system, and nothing to do with the actual starter motor itself, its purpose is to supply full battery voltage to the coils direct from the solenoid, but only while the starter is operating (by bypassing the ballast resistor) and that wire must be disconnected or removed when any type of electronic ignition is fitted.

Guys,

In the past I've swapped polarity on Jeeps, cars, bikes, boats, and Greyhound buses. There was never a starter motor issue.
The reasons for swapping were that all modern electronics on this side of the pond, stereos, navigation, etc were negative ground; and in the case of drivers it was one more error they could not make if they jumped it.
Since I don't plan to fit anything fancy on my personal Norton I see no reason for swapping.

Wiring now under progress and I, after deliberation and reading of articles, have decided to stick with the Positive earth. I am quite well on the way with it and I have stuck with the original wire colouring which will help no doubt.
Can someone enlighten me on this one, there is a Gray wire that runs from the switch in the R/H bar cluster and doesn't seem to do anything, in fact it's not even in the wiring diagram, it terminates in the 4 pin connector that also includes the white , white/ yellow & white/red which are the cut / start/ ignition wires. Now some of my wiring had been changed by PO that is one of the reasons I am doing the wiring, but I don't see a location for the gray at all, possibly an interplod use?

rbt11548 said:

Can someone enlighten me on this one, there is a Gray wire that runs from the switch in the R/H bar cluster and doesn't seem to do anything, in fact it's not even in the wiring diagram,

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But, a wire normally has two ends, :wink: - so a check of where the other end of the Grey wire went to inside the switch should have given you the answer you needed, or a switch wiring check with an ohmmeter would have found the relevant internal switch connections (between Grey and the White/Red with the starter button pressed).
In any case, the Grey wire should be the power feed wire to the starter push button switch, which should have a White wire feed connection to it on the opposing female pin of the 4-pin plug socket.

The 850 MkIII wiring diagram does actually show an internal jumper power wire between the ignition circuit White wire and the starter switch connection, but there appears to be no such wire fitted inside the switch housing.

L.A.B. said:

But, a wire normally has two ends, :wink: - so a check of where the other end of the Grey wire went to inside the switch should have given you the answer you needed, or a switch wiring check with an ohmmeter would have found the relevant internal switch connections (between Grey and the White/Red with the starter button pressed).
In any case, the Grey wire should be the power feed wire to the starter push button switch, which should have a White wire feed connection to it on the opposing female pin of the 4-pin plug socket.

The 850 MkIII wiring diagram does actually show an internal jumper power wire between the ignition circuit White wire and the starter switch connection, but there appears to be no such wire fitted inside the switch housing.

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Hi L.A.B. ,I had a look and lo and behold all wires have two ends :wink: on looking at the diagram closely there is indeed a jumper wire at the run /start buttons, I just wonder if intead of showing the gray wire running the full lentgh of the switch lead the have just shown it as the jump wire without a colour. I will check the switch in the morning. I also took pictures of the internails when I stripped the switches down to clean them. The gray wire did not connect to anything after the 4 way switch when I opened up the H/lamp , I was informed that the starter didn't work when I got the bike and am trying to sort the wiring out now so maybe that was the problem.

Just gone down to have a look, connected a multi meter lead to each wire to check for continuity... nothing ... press start button and ... continuity!, it must be the feed wire; what possessed Norton to put a gray feed to one switch when all the others are white!
Thanks

Possibly the switch internal wiring arrangement was changed by the factory (or more likely, by Lucas) at some point after the MkIII diagram had been drawn?

My own MkIII R/H switch unit has six wires, and not the five as drawn in the diagram (the switch has 1 x 4-pin & 1 x 2-pin plug) the 4-pin has two separate White wires connecting to it from the main harness, -one continues on to the switch unit from the other side of the plug as a White wire. The other changes over to Grey at the 4-pin plug.

The somewhat later Triumph twins (inc. elec.starts) also used a very similar R/H switch unit (the Triumph switch unit had separate bullet connectors on the wires and not plugs) and those units also have the Grey starter wire, curiously the Triumph electric start model wiring diagrams don't show that Grey wire either!

L.A.B. said:

My own MkIII R/H switch unit has six wires, and not the five as drawn in the diagram (the switch has 1 x 4-pin & 1 x 2-pin plug) the 4-pin has two separate White wires connecting to it from the main harness, -one continues on to the switch unit from the other side of the plug as a White wire. The other changes over to Grey at the 4-pin plug.

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Mine is exactly the same, (or would have been if there was a white wire going into the gray), probably cut for some obscure reason, Thing is I had noted all the connections down and took pictures before I started the wiring cull, sorry; the rewire! and there definitely wasn't a connection, either I missed it or as I said earlier it may have been cut by PO.

Just to ensure the rest of my starter wiring is there, on checking it should be:: Positive earth, electronic ignition fitted,
1 heavy wire from rear engine bolt to battery positive,
1 heavy wire from battery negative to solienoid,
1 heavy wire from soleniod to connection on top of starter
1 white /red wire from start switch to soleniod.

It looks as if the solenoid is just earthed by the bolts to the frame , would I be better running another earth from it?
Thanks

rbt11548 said:

Just to ensure the rest of my starter wiring is there, on checking it should be:: Positive earth, electronic ignition fitted,
1 heavy wire from rear engine bolt to battery positive,
1 heavy wire from battery negative to solienoid,
1 heavy wire from soleniod to connection on top of starter
1 white /red wire from start switch to soleniod.

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Yes that sounds correct, just make sure that the heavy starter positive wire is the ONLY return wire connection at the battery if you intend to use the starter motor.

rbt11548 said:

It looks as if the solenoid is just earthed by the bolts to the frame , would I be better running another earth from it?

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My solenoid works perfectly just being earthed to the frame by the bolts, although other members have said they've an earth wire fitted.

L.A.B. said:

Yes that sounds correct, just make sure that the heavy starter positive wire is the ONLY return wire connection at the battery if you intend to use the starter motor.

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Hi L.A.B., could you please explain the above a bit further, is the wiring earth not also attached to the battery or would it be better earthed to the frame.
Thanks

rbt11548 said:

could you please explain the above a bit further, is the wiring earth not also attached to the battery or would it be better earthed to the frame.

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Theoretically there should be no other harness return wires attached to the battery positive (Earth), only the heavy starter cable, the reason being that if a light gauge return wire is connected in addition to the heavy positive cable then if the heavy positive cable was to somehow become disconnected, loose, corroded or otherwise to go high resistance, then when the starter motor is operated, the starter amps (100A+) would attempt to return to the battery through the light gauge harness earth wire, result = smoke and/or flames!

It really was a silly thing for Norton to add a harness return connection to the battery, (Triumph did it on their T160 too!) you don't see it on other electric start vehicles.
Triumph soon issued a service bulletin to their dealers requesting them to remove the harness return positive wire from the battery and snip off its ring terminal on any T160 they encountered that still had it connected.

I don't know if the Norton factory ever issued a service bulletin about the problem, but the same should apply.


So I'd always run any harness earths to the engine (cylinder head) so the return to the battery is only through the heavy positive starter cable.

If the electric starter has been removed/disconnected/disabled then obviously there's no problem connecting the harness return wires directly to the battery.

And since you are on the subject of starter wiring. Throw away those old stock cables and make up a set of at least 6AWG cables using fine stranded wire (welding cable) for flexibility. A large part of the starter weakness is the too small cable that won't allow enough amperage to flow to the starter.

Ron L said:

Throw away those old stock cables and make up a set of at least 6AWG cables using fine stranded wire (welding cable) for flexibility.

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"6AWG" would be mostly unknown in the UK/Europe I would think (the UK didn't normally use AWG, only SWG) and now of course, we're metric.

VWP sells both welding and flexible starter cables. http://www.vehicle-wiring-products.eu/V ... ycable.php

I use the flexible 25 sq. mm 196/0.40 starter cable, and it is still a little bit stiff. I've been meaning to try some of the welding cable.

Ok gents will do!
Reason for only the heavy cable being attached is common sense when you think about it.
Thanks for all your help

6 AWG welding cable is generally 259 strands and 0.38" diameter. I have 4 AWG cable on my electric start cafe racer (374 strands/0.40" diameter) but this was probably overkill. The 6AWG will bend readily to follow frame contours.

I attach the ends to welding cable by crimping them a little and heating with a propane torch to solder. Then I use heat shrink tubing to cover it for a professional appearance. Oddly enough my local Interstate battery place carried large heat shink tubing.